Zinc plating bath and method of forming a non-dendritic zinc layer

Abstract

A method is described for forming a non-dendritic zinc layer which includes providing a deposition solution containing a zinc compound and from 0.001 to 10 weight percent of a non-ionic surfactant additive of oxaalkyl or polyoxaalkyl perfluoroalkane sulfonamide, positioning a pair of spaced apart electrodes within the solution, applying an electric current to the electrodes, and depositing a non-dendritic zinc layer on the negative electrode.

What we claim as new and desire to secure by Letters Patent of the U.S. is: 
     
       1. A method for forming a non-dendritic zinc layer which comprises providing a deposition solution containing a zinc compound and from 0.001 to 10 weight percent of a non-ionic surfactant additive which has the formula: ##STR4## where m is a number from 3 to 15, R is alkyl radical having from 1 to 10 carbon atoms, R 1  is a member of a group consisting of hydrogen and methyl radical, n is a number for the group from 0 to 30, and the surfactant additive has a molecular weight range of approximately 550-1500; positioning a pair of spaced apart electrodes within the deposition solution, applying an electric current to the electrodes, and depositing a non-dendritic zinc layer on the negative electrode. 
     
     
       2. A method for forming a non-dendritic zinc layer as in claim 1, in which there is present one percent by weight of the non-ionic surfactant additive. 
     
     
       3. A method for forming a non-dendritic zinc layer as in claim 1, in which there is present one-tenth percent by weight of the non-ionic surfactant additive. 
     
     
       4. A method for forming a non-dendritic zinc layer as in claim 1, in which the zinc compound is zinc bromide. 
     
     
       5. A method for forming a non-dendritic zinc layer as in claim 1, in which the zinc compound is zinc chloride. 
     
     
       6. A deposition solution comprising a solution containing a zinc compound, and from 0.001 to 10 weight percent of a non-ionic surfactant additive having the formula: ##STR5## where m is a number from 3 to 15, R is alkyl radical having from 1 to 10 carbon atoms, R 1  is a member of a group consisting of hydrogen and methyl radical, n is a number for the group from 0 to 30, and the surfactant additive has a molecular weight range of approximately 550-1500. 
     
     
       7. A deposition solution as in claim 6, in which the zinc compound is zinc bromide. 
     
     
       8. A deposition solution as in claim 6, in which the zinc compound is zinc chloride. 
     
     
       9. A deposition solution as in claim 6, in which the solution contains on a weight basis 62.4% H 2  O, 15.9% Z n  Br 2 , 15.9%, KBr, 3.2% Al 2  (SO 4 ) 3  and 1.6% H 3  BO 3 , and 1.0% of the non-ionic surfactant additive. 
     
     
       10. A deposition solution as in claim 6 in which the solution contains on a weight basis 63.3% H 2  O, 15.9% ZnBr 2 , 15.9% KBr, 3.2% Al 2  (SO 4 ) 3  and 1.6% H 3  BO 3 , and 0.1% of the non-ionic surfactant additive.